Composition of matter



COATING R PLASTIC.

Patented May 28, 19 29. 7'

UNITED STATES Examine PATENT OFFICE.

RALPH M. HARDGROVE, 0F ALLENTOW'N, PENNSYLVANIA, ASSIGNOR TO FULLER LE- HIGH COMPANY, OF FULLERTON, PENNSYLVANIA, A. CORPORATION 01? DELA- WARE.

COMPOSITION OF MATTER.

No Drawing.

This invention relates to a composition of matter to be used as a heat transmitting bond especially useful for certain purposes which will be explained. This invention is an improvement of that described in the application of Ervin G. Bailey, Serial No. 28,261, filed May 5, 1925.

In certain kinds of furnace construction and appurtenances to steam generators and furnaces it is desirable to have a heat conducting bonding material capable of being applied in plastic condition somewhat like a cement, and when hardened or set having the properties of adhesiveness and cohesiveness, to the extent that it will not disintegrate, and also being of a sufficiently refractory nature to be capable of resisting exposure to moderately high temperatures without detriment, but primarily having the property of relatively high conductivity of heat.

It is furthermore desirable that such material should be very plastic so that it will fit into and fill every crack and crevice when squeezed between two surfaces, and that it should be capable of drying, whether slowly or rapidly, with a minimum of porosity.

In certain types of furnace construction, it is necessary to form a union or bond between metal blocks, tiles, or refractory lining components, and tubes containing a circulating cooling medium by which the heat is abstracted from the lining sufiiciently to protect the latter from rapid deterioration by the high temperature and flame action.

In order effectively to perform its function of conducting the heat from one to the other of the components, the bond should be practically air and gas tight, and devoid, as far as possible, of air filled voids, and the purpose of the present invention is to produce a composition of matter having the requisite properties satisfactorily to meet all the requirements and of such nature that it can be made up in advance of its use and remain of the correct consistency while being used, without alteration due to drying while being applied.

The said material comprises a body portion of finely divided material of a sufficienly refractory and stable nature and a good conductor of heat, said body material being mingled with a suitable fluid and preferably cementitious substance serving as a vehicle to impart the necessary plasticity, which will dry out or set and form a solid union with Application filed May 17,

plastic 1927. Serial No. 192,164.

the particles of body material, water glass or sodium silicate being suitable for the cementitious component of the vehicle, contributing the property of adhesiveness to unite the particles of the pulverulent solid.

Mixtures of water glass with pulverized solid refractory material have been used in some cases as a refractory cement, but I have found that such composition is unsatisfactory as a bonding material for which the requirements are such as above indicated.

A water glass solution does not serve as a suitable vehicle in connection with the pulverulent heat conductive body material to produce the desired plastic bonding material for various reasons which need not be set forth in detail, among which is the fact that it dries too rapidly for effective handling and also results in a porous substance when set, of relatively low heat conductivity.

I have discovered that a mixture of erine water lass and a lubricatim oi sue as casr or Oll for exampl fie, a ords a suitable vehicle for the heat conduct'vg Egad ages; material and toge er erewl pro u s a bonding material which is readily workable and capable of application in the furnace construction as desired. The glycerine and oil act as a retarder to the evaporation of water from the mixture and have the efi'ect of producing a heat conductive material that is substantially free from pores and that provides a very effective bond or heat conducting union of the parts between which the material is interposed. In the furnace construction above referred to, the temperature to which the bonding material is exposed is usually somewhere between 200 and 400 Fahrenheit, and the bonding material forming the subject of this invention is of such nature that it will dry out and set into a dense cohesive solid when exposed to such temperature, so that a. furnace may be put into operation directly after the parts including the bonding'material have been installed, which admits of repair or replacement with the minimum loss of time.

I have found that various pulverulent conductive solid materials may be used as the body of the bonding material, such for example as finelv divided metal such as iron or are m genera more s ab e un er exposure to heat than metals.

erlne and 2 parts castor oil. although I have found that a suitable specific vehicle or flux to be incorporated with the solid pulverulent heat conductive body material is composed of approximately two parts of water lass with a specific gravity of 1.41 to one part "I 'ccrine of a specific gravity of 1.25, with sumtor oii to make about one to two percent 0 1e 0 a1 mixture.

I have also found that a very satisfactory body material for the purpose above stated is hematite. or carborundum. in very fine state, pre era y ner ian mesh, and a suitable proportion of the ingredients for an effective example of a composition of matter embodying this invention is 100 parts carborundum. to 40 parts water lass. 20 parts lveesire it to be unders 00 t a the invention is not limited to these specific materials or proportions.

I claim:

1. A composition of matter comprising pulverulent heat conducting material and a bonding mixture containing water glass, glycerine and oil which is substantially free from pores when dry.

2. A composition of matter comprising pulverulent heat conducting material and a bonding mixture containing water glass, glycerine and lubricating oil which is substantially free from pores when dry.

3. A composition of matter comprising pulverulent heat conducting material and a bonding mixture containing water glass, glycerine and castor oil.

4. A composition of matter comprising finely divided carborundum, water glass, glycerine and oil.

5. A composition of matter comprising finely divided carborundum, water glass, glycerine and castor oil.

6. A composition of matter comprising pulverulent heat conducting material and a bonding mixture containing water glass. glycerine and oil with the proportions of water glass to glycerine to oil about 20 to 10 to 1.

7. A composition of matter comprising finely divided carborundum, water glass, glycerine and oil in substantially the proportions of 100 parts of carborundum to 40 parts of water glass to 20 parts of glycerine to 2 parts of castor oil.

RALPH M. HARDGROVE. 

